Polarographic determination of malononitrile.

A procedure is proposed for the determination of malononitrile by differential pulse polarography in methanolic 0.1M tetraethylammonium iodide/0.001M tetramethylammonium hydroxide as the supporting electrolyte. In this medium malononitrile is chemically converted into an electroactive species. With close control of timing of the steps in the procedure the error of the method is +/-1.5% in the concentration range 0.0001-0.001M. Acrylonitrile, benzonitrile and succinic acid dinitrile do not interfere.